Refer to this documentation for configuring chrony time service.
In this example, I have followed the documentation to customize the /etc/chrony.conf using the contents of example-chrony.conf to use the clock.redhat.com NTP server. I stepped through the documentation to generate the MachineConfigs for masters and workers.
Then, I applied the chrony configuration MachineConfigs to the cluster with:
oc apply -f 99-master-chrony-configuration.yaml
oc apply -f 99-worker-chrony-configuration.yaml